Arduino coding of producing frequency

Question

Im new here. Anyone that could give a code or sample that would generate I wanted to use a frequency in range of 35k-43kHz. Please help me.

• Gerben: Sound a lot like an IR carrier wave.

Answer 1

The code below generates 38 kHz and modulates its duty cycle.

// Example of modulating a 38 kHz frequency duty cycle by reading a potentiometer
// Author: Nick Gammon
// Date: 24 September 2012
const byte POTENTIOMETER = A0;
const byte LED = 10; // Timer 1 "B" output: OC1B
// Clock frequency divided by 38 kHz frequency desired
const long timer1_OCR1A_Setting = F_CPU / 38000L;
void setup() 
 {
 pinMode (LED, OUTPUT);
 // set up Timer 1 - gives us 38.005 kHz 
 // Fast PWM top at OCR1A
 TCCR1A = bit (WGM10) | bit (WGM11) | bit (COM1B1); // fast PWM, clear OC1B on compare
 TCCR1B = bit (WGM12) | bit (WGM13) | bit (CS10); // fast PWM, no prescaler
 OCR1A = timer1_OCR1A_Setting - 1; // zero relative 
 } // end of setup
void loop()
 {
 // alter Timer 1 duty cycle in accordance with pot reading
 OCR1B = (((long) (analogRead (POTENTIOMETER) + 1) * timer1_OCR1A_Setting) / 1024L) - 1;
 // do other stuff here
 }

• Gerben: Just to add; this code works for pin 10, and pin 10 alone.
• user13535: I connected the output to the ultrasonic transmitter but its not working. here is the transmitter specification that i used (farnell.com/datasheets/1498178.pdf) and the circuit diagram (google.com.ph/…)
• Nick Gammon: Not working? How do you know? Are you getting 38 kHz out of the Arduino or not? You would need an oscilloscope to check.

Answer 2

use the 'tone' function: arduino tone function

example:

//tone(pinNumber, FrequencyInHertz);
tone(6, 35000); //generate a 35kHz tone on pin 6
delay(10);
tone(6, 43000); //generate a 43kHz tone on pin 6

• Nick Gammon: Could you elaborate a bit? This is basically a link-only answer which would not be helpful if the link went down.
• user13535: I wanted to generate a set of high frequency at the range of 25k-60k Hz using the arduino uno. Please help me. What function do i use? I'm a newbie on coding and if anyone would share some code it would be a great help. Im very thankful.
• CharlieHanson: @user13535 You now say 25k-60kHz, but your question says 38k-43kHz. Which is it?
• user13535: The 25k-60k Hz. I change the range.

Answer 3

This is meant to be a comment, but I can't put (pseudo) code in a comment.

A 40 kHz square wave? Simple:

for(;;){
 wait ( 1 / 2 * 40.000 );
 make pin high;
 wait ( 1 / 2 * 40.000 );
 make pin low;
}